Organometallic compound and organic light-emitting device including the same

ABSTRACT

An organometallic compound represented by Formula 1 and an organic light-emitting device including the same:Y2, ring A2, R1 to R8, R13 to R20, and d2 in Formula 1 may be each independently the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application of U.S. application Ser. No. 16/669,760, filed Oct. 31, 2019, which claims the benefit of Korean Patent Applications Nos. 10-2018-0173083, filed on Dec. 28, 2018, and 10-2019-0136792, filed on Oct. 30, 2019, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which are incorporated herein in their entirety by reference.

BACKGROUND 1. Field

The present disclosure relates to an organometallic compound and an organic light-emitting device including the same.

2. Description of the Related Art

Organic light-emitting devices are self-emission devices, which have improved characteristics in terms of viewing angles, response times, brightness, driving voltages, and response speeds, and produce full-color images.

In an example, an organic light-emitting device includes an anode, a cathode, and an organic layer between the anode and the cathode, wherein the organic layer includes an emission layer. A hole transport region may be between the anode and the emission layer, and an electron transport region may be between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light.

SUMMARY

Provided are novel organometallic compounds and organic light-emitting devices including the same.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to an aspect of an embodiment, an organometallic compound represented by Formula 1:

In Formula 1,

-   -   Y₂ may be C,     -   ring A₂ may be a C₅-C₃₀ carbocyclic group or a C₁-C₃₀         heterocyclic group,     -   R₁ to R₈, R₁₃ to R₁₇, and R₂₀ may each independently be         hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid or a salt         thereof, a sulfonic acid or a salt thereof, a phosphoric acid or         a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl         group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a         substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted         or unsubstituted C₁-C₆₀ alkoxy group, a substituted or         unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or         unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or         unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or         unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or         unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted         C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀         arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl         group, a substituted or unsubstituted monovalent non-aromatic         condensed polycyclic group, a substituted or unsubstituted         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇),         —P(═O)(Q₈)(Q₉>, or —P(Q₈)(Q₉),     -   d2 may be an integer from 0 to 10, and when d2 is 2 or more, two         or more R₂₀(s) may be identical to or different from each other,     -   i) at least one of R₁ to R₈ may include at least one fluoro         group (—F), and ii) R₂₀ may include neither a fluoro group (—F)         nor a cyano group,     -   R₁₈ and R₁₉ may each independently be a substituted or         unsubstituted C₂-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or         unsubstituted C₆-C₁₀ aryloxy group, a substituted or         unsubstituted C₆-C₁₀ arylthio group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, or a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group,     -   two or more of R₁ to R₈ may be optionally linked to form a         C₅-C₃₀ carbocyclic group which is unsubstituted or substituted         with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is         unsubstituted or substituted with at least one R_(1a),     -   two or more of R₂₀(s) in the number of d2 may be optionally         linked to form a C₅-C₃₀ carbocyclic group which is unsubstituted         or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic         group which is unsubstituted or substituted with at least one         R_(1a),     -   two or more of R₁₃ to R₁₉ may be optionally linked to form a         C₅-C₃₀ carbocyclic group which is unsubstituted or substituted         with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is         unsubstituted or substituted with at least one R_(1a),     -   R_(1a) may be the same as explained in connection with R₂,     -   a substituent of the substituted C₁-C₆₀ alkyl group, the         substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl         group, the substituted C₁-C₆₀ alkoxy group, the substituted         C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀ heterocycloalkyl         group, the substituted C₃-C₁₀ cycloalkenyl group, the         substituted C₂-C₁₀ heterocycloalkenyl group, the substituted         C₆-C₁₀ aryl group, the substituted C₆-C₁₀ aryloxy group, the         substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀         heteroaryl group, the substituted monovalent non-aromatic         condensed polycyclic group, and the substituted monovalent         non-aromatic condensed heteropolycyclic group is:     -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid or a salt thereof, a sulfonic acid or a salt         thereof, a phosphoric acid or a salt thereof, a C₁-C₆₀ alkyl         group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a         C₁-C₆₀ alkoxy group, or any combination thereof;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, or a C₁-C₆₀ alkoxy group, each substituted with         deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid or a salt thereof, a sulfonic acid or a salt         thereof, a phosphoric acid or a salt thereof, a C₃-C₁₀         cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀         cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀         aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₁₀ arylthio group, a         C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed         polycyclic group, a monovalent non-aromatic condensed         heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅),         —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), —P(═O)(Q₁₈)(Q₁₉),         —P(Q₁₈)(Q₁₉), or any combination thereof;     -   a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a         C₆-C₁₀ aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, or a monovalent non-aromatic         condensed heteropolycyclic group, each unsubstituted or         substituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid or a salt thereof, a         sulfonic acid or a salt thereof, a phosphoric acid or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀ aryl group, a C₆-C₁₀         aryloxy group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl         group, a monovalent non-aromatic condensed polycyclic group, a         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅),         —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), —P(Q₂₈)(Q₂₉), or any combination         thereof;     -   —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅),         —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), or —P(Q₃₈)(Q₃₉), or any         combination thereof; or     -   any combination thereof,     -   wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may         each independently be: hydrogen; deuterium; —F; —Cl; —Br; —I; a         hydroxyl group; a cyano group; a nitro group; an amidino group;         a hydrazine group; a hydrazone group; a carboxylic acid group or         a salt thereof; a sulfonic acid group or a salt thereof; a         phosphoric acid group or a salt thereof; a C₁-C₆₀ alkyl group,         unsubstituted or substituted with deuterium, a C₁-C₆₀ alkyl         group, a C₆-C₆₀ aryl group, or any combination thereof; a C₂-C₆₀         alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; a         C₃-C₁₀ cycloalkyl group; a C₂-C₁₀ heterocycloalkyl group; a         C₃-C₁₀ cycloalkenyl group; a C₂-C₁₀ heterocycloalkenyl group; a         C₆-C₁₀ aryl group, unsubstituted or substituted with deuterium,         a C₁-C₆₀ alkyl group, a C₆-C₁₀ aryl group, or any combination         thereof; a C₆-C₁₀ aryloxy group; a C₆-C₁₀ arylthio group; a         C₁-C₆₀ heteroaryl group; a monovalent non-aromatic condensed         polycyclic group; or a monovalent non-aromatic condensed         heteropolycyclic group.

Another aspect provides an organic light-emitting device including a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode and including an emission layer, wherein the organic layer includes at least one organometallic compounds represented by Formula 1.

The organometallic compound in the emission layer of the organic layer may function as a dopant.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with FIGURE which is a schematic cross-sectional view of an organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present

It will be understood that, although the terms “first,” “second,” “third” etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section Thus, “a first element,” “component,” “region,” “layer” or “section” discussed below could be termed a second element, component, region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, “a,” “an,” “the,” and “at least one” do not denote a limitation of quantity, and are intended to cover both the singular and plural, unless the context clearly indicates otherwise. For example, “an element” has the same meaning as “at least one element,” unless the context clearly indicates otherwise.

“Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the Figures It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements The exemplary term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on the particular orientation of the figure Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features Moreover, sharp angles that are illustrated may be rounded Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

An organometallic compound according to one embodiment is represented by Formula 1 below:

-   -   Y₂ in Formula 1 may be C.     -   Ring A₂ in Formula 1 may be a C₅-C₃₀ carbocyclic group or a         C₁-C₃₀ heterocyclic group.

For example, ring A₂ in Formula 1 may be i) a first ring, ii) a second ring, iii) a condensed cyclic group in which two or more first rings are condensed with each other, iv) a condensed cyclic group in which two or more second rings are condensed with each other, or v) a condensed cyclic group in which at least one first ring is condensed with at least one second ring,

-   -   the first ring may be a cyclopentane group, a cyclopentadiene         group, a furan group, a thiophene group, a pyrrole group, a         silole group, an indene group, a benzofuran group, a         benzothiophene group, an indole group, a benzosilole group, an         oxazole group, an isoxazole group, an oxadiazole group, an         isoxadiazole group, an oxatriazole group, an isoxatriazole         group, a thiazole group, an isothiazole group, a thiadiazole         group, an isothiadiazole group, a thiatriazole group, an         isothiatriazole group, a pyrazole group, an imidazole group, a         triazole group, a tetrazole group, an azasilole group, a         diazasilole group, or a triazasilole group,     -   the second ring may be an adamantane group, a norbornene group,         a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a         bicyclo[2.2.1]heptane group (a norbornane group), a         bicyclo[2.2.2]octane group, a cyclohexane group, a cyclohexene         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, or a triazine group.

In one or more embodiments, ring A₂ in Formula 1 may be a cyclopentane group, a cyclohexane group, a cyclohexene group, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a thiophene group, a furan group, a pyrrole group, a cyclopentadiene group, a silole group, a borole group, a phosphole group, a selenophene group, a germole group, a benzothiophene group, a benzofuran group, an indole group, an indene group, a benzosilole group, a benzoborole group, a benzophosphole group, a benzoselenophene group, a benzogermole group, a dibenzothiophene group, a dibenzofuran group, a carbazole group, a fluorene group, a dibenzosilole group, a dibenzoborole group, a dibenzophosphole group, a dibenzoselenophene group, a dibenzogermole group, a dibenzothiophene 5-oxide group, 9H-fluorene-9-one group, a dibenzothiophene 5,5-dioxide group, an azabenzothiophene group, an azabenzofuran group, an azaindole group, an azaindene group, an azabenzosilole group, an azabenzoborole group, an azabenzophosphole group, an azabenzoselenophene group, an azabenzogermole group, an azadibenzothiophene group, an azadibenzofuran group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzoborole group, an azadibenzophosphole group, an azadibenzoselenophene group, an azadibenzogermole group, an azadibenzothiophene 5-oxide group, an aza-9H-fluorene-9-one group, an azadibenzothiophene 5,5-dioxide group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isooxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, a 5,6,7,8-tetrahydroquinoline group, an adamantane group, a norbornane group, or a norbornene group.

In one or more embodiments, ring A₂ may be a benzene group, a naphthalene group, a 1, 2, 3, 4-tetrahydronaphthalene group, a thiophene group, a furan group, a pyrrole group, a cyclopentadiene group, a silole group, a benzothiophene group, a benzofuran group, an indole group, an indene group, a benzosilole group, a dibenzothiophene group, a dibenzofuran group, a carbazole group, a fluorene group, or a dibenzosilole group.

R₁ to R₈, R₁₃ to R₁₇, and R₂₀ in Formula 1 may each independently be hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), or —P(Q₈)(Q₉). Each of Q₁ to Q₉ are the same as described herein. Herein, R₂₀ may include neither a fluoro group (—F) nor a cyano group. In one or more embodiments, R₂₀ may be a group that includes neither a fluoro group (—F) nor a cyano group.

For example, R₁ to R₈, and R₁₃ to R₁₇ and R₂₀ in Formula 1 may each independently be:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid or a salt         thereof, a sulfonic acid or a salt thereof, a phosphoric acid or         a salt thereof, —SF₅, a C₁-C₂₀ alkyl group, or a C₁-C₂₀ alkoxy         group;     -   a C₁-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted         with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,         —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₂₀ alkyl group, a deuterium-containing C₁-C₂₀         alkyl group, a fluorinated C₁-C₂₀ alkyl group, a cyclopentyl         group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl         group, an adamantyl group, a norbornenyl group, a cyclopentenyl         group, a cyclohexenyl group, a cycloheptenyl group, a         bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a         bicyclo[2.2.1]heptyl group (a norbornyl group), a         bicyclo[2.2.2]octyl group, a (C₁-C₂₀ alkyl)cyclopentyl group, a         (C₁-C₂₀ alkyl)cyclohexyl group, a (C₁-C₂₀ alkyl)cycloheptyl         group, a (C₁-C₂₀ alkyl)cyclooctyl group, a (C₁-C₂₀         alkyl)adamantyl group, a (C₁-C₂₀ alkyl)norbornenyl group, a         (C₁-C₂₀ alkyl)cyclopentenyl group, a (C₁-C₂₀ alkyl)cyclohexenyl         group, a (C₁-C₂₀ alkyl)cycloheptenyl group, a (C₁-C₂₀         alkyl)bicyclo[1.1.1]pentyl group, a (C₁-C₂₀         alkyl)bicyclo[2.1.1]hexyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.1]heptyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.2]octyl group, a silolanyl group, a phenyl         group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, a 1,2,3,4-tetrahydronaphthyl         group, a pyridinyl group, a pyrimidinyl group, or any         combination thereof,     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl         group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl         group, a silolanyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl         group, a biphenyl group, a terphenyl group, a naphthyl group, a         1,2,3,4-tetrahydronaphthyl group, a fluorenyl group, a         phenanthrenyl group, an anthracenyl group, a fluoranthenyl         group, a triphenylenyl group, a pyrenyl group, a chrysenyl         group, a pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, an         imidazopyrimidinyl group, an azacarbazolyl group, an         azadibenzofuranyl group, or an azadibenzothiophenyl group, each         unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I,         —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         deuterium-containing C₁-C₂₀ alkyl group, a fluorinated C₁-C₂₀         alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantyl group, a norbornenyl group, a cyclopentenyl group, a         cyclohexenyl group, a cycloheptenyl group, a         bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a         bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a         (C₁-C₂₀ alkyl)cyclopentyl group, a (C₁-C₂₀ alkyl)cyclohexyl         group, a (C₁-C₂₀ alkyl)cycloheptyl group, a (C₁-C₂₀         alkyl)cyclooctyl group, a (C₁-C₂₀ alkyl)adamantyl group, a         (C₁-C₂₀ alkyl)norbornenyl group, a (C₁-C₂₀ alkyl)cyclopentenyl         group, a (C₁-C₂₀ alkyl)cyclohexenyl group, a (C₁-C₂₀         alkyl)cycloheptenyl group, a (C₁-C₂₀ alkyl)bicyclo[1.1.1]pentyl         group, a (C₁-C₂₀ alkyl)bicyclo[2.1.1]hexyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.1]heptyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.2]octyl group, a silolanyl group, a phenyl         group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, a 1,2,3,4-tetrahydronaphthyl         group, a fluorenyl group, a phenanthrenyl group, an anthracenyl         group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl         group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,         a furanyl group, an imidazolyl group, a pyrazolyl group, a         thiazolyl group, an isothiazolyl group, an oxazolyl group, an         isoxazolyl group, a pyridinyl group, a pyrazinyl group, a         pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an         indolyl group, an indazolyl group, a purinyl group, a quinolinyl         group, an isoquinolinyl group, a benzoquinolinyl group, a         quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a         carbazolyl group, a phenanthrolinyl group, a benzimidazolyl         group, a benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, an         imidazopyrimidinyl group, an azacarbazolyl group, an         azadibenzofuranyl group, an azadibenzothiophenyl group, or any         combination thereof; or     -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇),         —P(═O)(Q₈)(Q₉>, or —P(Q₈)(Q₉), wherein R₂₀ includes neither a         fluoro group nor a cyano group,     -   Q₁ to Q₉ may each independently be:     -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H or         —CD₂CDH₂; or     -   an n-propyl group, an isopropyl group, an n-butyl group, a         sec-butyl group, an isobutyl group, a tert-butyl group, an         n-pentyl group, a tert-pentyl group, a neopentyl group, an         isopentyl group, a sec-pentyl group, a 3-pentyl group, a         sec-isopentyl group, a phenyl group, a biphenyl group, or a         naphthyl group, each unsubstituted or substituted with         deuterium, a C₁-C₂₀ alkyl group, a phenyl group, or any         combination thereof.

In one or more embodiments, R₁ to R₈, R₁₃ to R₁₇, and R₂₀ in Formula 1 may each independently be hydrogen, deuterium, —F, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅). Herein, R₂₀ may include neither a fluoro group nor a cyano group.

In one or more embodiments, R₁ to R₈ and R₁₃ to R₁₇ in Formula 1 may each independently be:

-   -   hydrogen, deuterium, or —F;     -   a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀         heterocycloalkyl group, each unsubstituted or substituted with         deuterium, —F, C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a         C₂-C₁₀ heterocycloalkyl group, or any combination thereof; or         —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅).

In one or more embodiments, R₂₀ in Formula 1 may be:

-   -   hydrogen or deuterium;     -   a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀         heterocycloalkyl group, each unsubstituted or substituted with         deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a         C₂-C₁₀ heterocycloalkyl group, or any combination thereof; or     -   —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅).

The designation d2 in Formula 1 indicates the number of R₂₀(s), and may be an integer from 0 to 10. When d2 is 2 or more, two or more R₂₀(s) may be identical to or different from each other. For example, d2 may be an integer from 0 to 6.

In one or more embodiments, at least one of R₁ to R₈ in Formula 1 may include at least one fluoro group (—F).

In one or more embodiments, at least one of R₁ to R₈ of Formula 1 may be a group including at least one fluoro group (—F).

In one or more embodiments, at least one of R₁ to R₈ in Formula 1 may each independently be:

-   -   a fluoro group (—F); or     -   a fluorinated C₁-C₂₀ alkyl group, a fluorinated C₃-C₁₀         cycloalkyl group, or a fluorinated C₂-C₁₀ heterocycloalkyl         group, each unsubstituted or substituted with deuterium, a         C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀         heterocycloalkyl group, or any combination thereof.

R₁₈ and R₁₉ in Formula 1 may each independently be a substituted or unsubstituted C₂-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

For example, R₁₈ and R₁₉ in Formula 1 may each independently be:

-   -   a C₂-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group;     -   a C₂-C₂₀ alkyl group or a C₁-C₂₀ alkoxy group, each substituted         with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,         —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₂₀ alkyl group, a deuterium-containing C₁-C₂₀         alkyl group, a fluorinated C₁-C₂₀ alkyl group, a cyclopentyl         group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl         group, an adamantyl group, a norbornenyl group, a cyclopentenyl         group, a cyclohexenyl group, a cycloheptenyl group, a         bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a         bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a         (C₁-C₂₀ alkyl)cyclopentyl group, a (C₁-C₂₀ alkyl)cyclohexyl         group, a (C₁-C₂₀ alkyl)cycloheptyl group, a (C₁-C₂₀         alkyl)cyclooctyl group, a (C₁-C₂₀ alkyl)adamantyl group, a         (C₁-C₂₀ alkyl)norbornenyl group, a (C₁-C₂₀ alkyl)cyclopentenyl         group, a (C₁-C₂₀ alkyl)cyclohexenyl group, a (C₁-C₂₀         alkyl)cycloheptenyl group, a (C₁-C₂₀ alkyl)bicyclo[1.1.1]pentyl         group, a (C₁-C₂₀ alkyl)bicyclo[2.1.1]hexyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.1]heptyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.2]octyl group, a silolanyl group, a phenyl         group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, a 1,2,3,4-tetrahydronaphthyl         group, a pyridinyl group, a pyrimidinyl group, or any         combination thereof; or     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl         group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl         group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl         group, a terphenyl group, a naphthyl group, a         1,2,3,4-tetrahydronaphthyl group, a fluorenyl group, a         phenanthrenyl group, an anthracenyl group, a fluoranthenyl         group, a triphenylenyl group, a pyrenyl group, a chrysenyl         group, a pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, an         imidazopyrimidinyl group, an azacarbazolyl group, an         azadibenzofuranyl group, or an azadibenzothiophenyl group, each         unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I,         —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         deuterium-containing C₁-C₂₀ alkyl group, a fluorinated C₁-C₂₀         alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantyl group, a norbornenyl group, a cyclopentenyl group, a         cyclohexenyl group, a cycloheptenyl group, a         bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a         bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a         (C₁-C₂₀ alkyl)cyclopentyl group, a (C₁-C₂₀ alkyl)cyclohexyl         group, a (C₁-C₂₀ alkyl)cycloheptyl group, a (C₁-C₂₀         alkyl)cyclooctyl group, a (C₁-C₂₀ alkyl)adamantyl group, a         (C₁-C₂₀ alkyl)norbornenyl group, a (C₁-C₂₀ alkyl)cyclopentenyl         group, a (C₁-C₂₀ alkyl)cyclohexenyl group, a (C₁-C₂₀         alkyl)cycloheptenyl group, a (C₁-C₂₀ alkyl)bicyclo[1.1.1]pentyl         group, a (C₁-C₂₀ alkyl)bicyclo[2.1.1]hexyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.1]heptyl group, a (C₁-C₂₀         alkyl)bicyclo[2.2.2]octyl group, a silolanyl group, a phenyl         group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a         terphenyl group, a naphthyl group, a 1,2,3,4-tetrahydronaphthyl         group, a fluorenyl group, a phenanthrenyl group, an anthracenyl         group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl         group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,         a furanyl group, an imidazolyl group, a pyrazolyl group, a         thiazolyl group, an isothiazolyl group, an oxazolyl group, an         isoxazolyl group, a pyridinyl group, a pyrazinyl group, a         pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an         indolyl group, an indazolyl group, a purinyl group, a quinolinyl         group, an isoquinolinyl group, a benzoquinolinyl group, a         quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a         carbazolyl group, a phenanthrolinyl group, a benzimidazolyl         group, a benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, an         imidazopyrimidinyl group, an azacarbazolyl group, an         azadibenzofuranyl group, an azadibenzothiophenyl group, or any         combination thereof.

In one or more embodiments, R₁₈ and R₁₉ in Formula 1 may each independently be a substituted or unsubstituted C₂-C₆₀ alkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, or a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group.

In one or more embodiments, R₁₈ and R₁₉ in Formula 1 may each independently be a C₂-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, —F, C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

For example, R₁ to R₈ and R₁₃ to R₁₇ in Formula 1 may each independently be hydrogen, deuterium, —F, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a group represented by one of Formulae 9-1 to 9-39, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 9-201 to 9-233, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-1 to 10-126, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-201 to 10-343, a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with —F, —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅) (herein Q₃ to Q₅ are the same as described in the present specification), and at least one of R₁ to R₈ may be —F, —CF₃, —CF₂H, —CFH₂, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with —F, or a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with —F.

In one or more embodiments, R₂₀ in Formula 1 may be hydrogen, deuterium, —CH₃, —CD₃, —CD₂H, —CDH₂, a group represented by one of Formulae 9-1 to 9-39, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-201 to 9-233, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-1 to 10-126, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-201 to 10-343, a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with deuterium, —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅) (herein Q₃ to Q₅ are the same as described in the present specification).

In one or more embodiments, R₁₈ and R₁₉ in Formula 1 may each independently be a group represented by one of Formulae 9-1 to 9-39, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 9-201 to 9-233, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-1 to 10-126, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with deuterium, a group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with —F, a group represented by one of Formulae 10-201 to 10-343, a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with deuterium, or a group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with —F:

* in Formulae 9-1 to 9-39, 9-201 to 9-233, 10-1 to 10-126, and 10-201 to 10-343 indicates a binding site to a neighboring atom, Ph is a phenyl group, TMS is a trimethylsilyl group, and TMG is a trimethylgermyl group.

The “group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with deuterium” and the “group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with deuterium” may each be, for example, a group represented by one of Formulae 9-501 to 9-514 and 9-601 to 9-635:

The “group represented by one of Formulae 9-1 to 9-39 in which at least one hydrogen is substituted with —F” and the “group represented by one of Formulae 9-201 to 9-233 in which at least one hydrogen is substituted with —F” may each be, for example, a group represented by one of Formulae 9-701 to 9-710:

The “group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with deuterium” and the “group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with deuterium” may each be, for example, a group represented by one of Formulae 10-501 to 10-553:

The “group represented by one of Formulae 10-1 to 10-126 in which at least one hydrogen is substituted with —F” and the “group represented by one of Formulae 10-201 to 10-343 in which at least one hydrogen is substituted with —F” may each be, for example, a group represented by one of Formulae 10-601 to 10-615:

In one or more embodiments, at least one of R₄ to R₈ of Formula 1 (for example, one or two of R₄ to R₈) may include at least one fluoro group (—F).

In one or more embodiments, in Formula 1,

-   -   1) R₄ may include at least one fluoro group (—F);     -   2) R₅ may include at least one fluoro group (—F);     -   3) R₆ may include at least one fluoro group (—F);     -   4) R₇ may include at least one fluoro group (—F);     -   5) R₈ may include at least one fluoro group (—F);     -   6) R₅ and R₆ may each include at least one fluoro group (—F);     -   7) R₅ and R₇ may each include at least one fluoro group (—F);     -   8) R₅ and R₈ may each include at least one fluoro group (—F);     -   9) R₆ and R₇ may each include at least one fluoro group (—F);     -   10) R₆ and R₈ may each include at least one fluoro group (—F);         or     -   11) R₇ and R₈ may each include at least one fluoro group (—F).

In one or more embodiments, regarding Formula 1,

-   -   one or two of R₁ to R₈ may each independently include at least         one fluoro group (—F), and     -   at least one of R₁ to R₈ i) may not include a fluoro group (—F),         and ii) may not be hydrogen.

In one or more embodiments, at least one of R₁ and R₃ in Formula 1 may not be hydrogen.

In one or more embodiments, R₂₀ in Formula 1 may be a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In one or more embodiments, R₂₀ in Formula 1 may be a C₁-C₂₀ alkyl group, unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, or any combination thereof.

In one or more embodiments, d2 in Formula 1 may be 2.

In one or more embodiments, R₂₀ in Formula 1 may be a C₁-C₂₀ alkyl group, unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, or any combination thereof, and d2 may be 2.

In one or more embodiments, the organometallic compound represented by Formula 1 may have at least one deuterium.

In one or more embodiments, at least one of R₁ to R₈ of Formula 1 may have at least one deuterium.

In one or more embodiments, at least one of R₂₀ in number of d2 may have at least one deuterium.

In one or more embodiments, at least one of R₂₀ in number of d2 may be a deuterium-containing C₁-C₂₀ alkyl group, a deuterium-containing C₃-C₁₀ cycloalkyl group, or a deuterium-containing C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In Formula 1, 1) two or more of R₁ to R₈ may be optionally linked to each other to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a), 2) two or more of R₂₀(s) in the number of d2 may be optionally linked to each other to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a), and 3) two or more of R₁₃ to R₁₉ may be optionally linked to each other to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a). Herein, R_(1a) may be understood by referring to the description of R₂.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclic group or a polycyclic group. The term “C₅-C₃₀ carbocyclic group (which is unsubstituted or substituted with at least one R_(1a))” may include, for example, an adamantane group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.1]heptane group (a norbornane group), a bicyclo[2.2.2]octane group, a cyclopentane group, a cyclohexane group, a cyclohexene group, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, cyclopentadiene group, and a fluorene group, each being unsubstituted or substituted with at least one R_(1a).

The term “C₁-C₃₀ heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring forming atom, at least one heteroatom selected from N, O, Si, P, and S other than 1 to 30 carbon atoms, The C₁-C₃₀ heterocyclic group may be a monocyclic group or a polycyclic group. The C₁-C₃₀ heterocyclic group (which is unsubstituted or substituted with at least one R_(1a))” may include, for example, a thiophene group, a furan group, a pyrrole group, a a silole group, a borole group, a phosphole group, a selenophene group, a germole group, a benzothiophene group, a benzofuran group, an indole group, an indene group, a benzosilole group, a benzoborole group, a benzophosphole group, a benzoselenophene group, a benzogermole group, a dibenzothiophene group, a dibenzofuran group, a carbazole group, a dibenzosilole group, a dibenzoborole group, a dibenzophosphole group, a dibenzoselenophene group, a dibenzogermole group, a dibenzothiophene 5-oxide group, 9H-fluorene-9-one group, a dibenzothiophene 5,5-dioxide group, an azabenzothiophene group, an azabenzofuran group, an azaindole group, an azaindene group, an azabenzosilole group, an azabenzoborole group, an azabenzophosphole group, an azabenzoselenophene group, an azabenzogermole group, an azadibenzothiophene group, an azadibenzofuran group, an azacarbazole group, an azafluorene group, an azadibenzosilole group, an azadibenzoborole group, an azadibenzophosphole group, an azadibenzoselenophene group, an azadibenzogermole group, an azadibenzothiophene 5-oxide group, an aza-9H-fluorene-9-one group, an azadibenzothiophene 5,5-dioxide group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isooxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a benzopyrazole group, a benzimidazole group, a benzoxazole group, a benzothiazole group, a benzoxadiazole group, a benzothiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group, each being unsubstituted or substituted with at least one R_(1a).

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof include a methyl group, an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an isoamyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group” used herein refers to a divalent group having the same structure as that of the C₁-C₆₀ alkyl group.

Non-limiting examples of the C₁-C₆₀ alkyl group, the C₁-C₂₀ alkyl group, and/or the C₁-C₁₀ alkyl group are a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, and a tert-decyl group, each unsubstituted or substituted with a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, a neopentyl group, an isopentyl group, a sec-pentyl group, a 3-pentyl group, a sec-isopentyl group, an n-hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, an n-heptyl group, an isoheptyl group, a sec-heptyl group, a tert-heptyl group, an n-octyl group, an isooctyl group, a sec-octyl group, a tert-octyl group, an n-nonyl group, an isononyl group, a sec-nonyl group, a tert-nonyl group, an n-decyl group, an isodecyl group, a sec-decyl group, a tert-decyl group, or any combination thereof. For example, Formula 9-33 may be a branched C₆ alkyl group, and may be a tert-butyl group that is substituted with two methyl groups.

The term “C₁-C₆₀ alkoxy group” used herein refers to a monovalent group represented by—OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and examples thereof include a methoxy group, an ethoxy group, and an isopropyloxy group. Non-limiting examples of the C₁-C₆₀ alkoxy group, the C₁-C₂₀ alkoxy group, or the C₁-C₁₀ alkoxy group are a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent group having the same structure as that of the C₃-C₁₀ cycloalkyl group. Non-limiting examples of the C₃-C₁₀ cycloalkyl group are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantyl group, a bicyclo[1.1.1]pentyl group (bicyclo[1.1.1]pentyl), a bicyclo[2.1.1]hexyl group (bicyclo[2.1.1]hexyl), a bicyclo[2.2.1]heptyl group (bicyclo[2.2.1]heptyl)(a norbornyl group), and a bicyclo[2.2.2]octyl group.

The term “C₂-C₁₀ heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom of N, O, P, Si, Se, Ge, or S as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₂-C₁₀ heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C₂-C₁₀ heterocycloalkyl group. Non-limiting examples of the C₂-C₁₀ heterocycloalkyl group are a silolanyl group, a silinanyl group, a tetrahydrofuranyl group, a tetrahydro-2H-pyranyl group, and a tetrahydrothiophenyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbon group formed by substituting at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalent group having the same structure as that of the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbon group formed by substituting at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group” as used herein refers to a divalent group having the same structure as that of the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and no aromaticity, and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₂-C₁₀ heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, Si, Se, Ge, B, or S as a ring-forming atom, 1 to 10 carbon atoms, and at least one double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₂-C₁₀ heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₂-C₁₀ heterocycloalkenyl group.

The term “C₆-C₁₀ aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₁₀ arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₁₀ aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₁₀ aryl group and the C₆-C₁₀ arylene group each include two or more rings, the rings may be fused to each other.

The term “C₇-C₆₀ alkylaryl group” used herein refers to a C₆-C₅₉ aryl group substituted with at least one C₁-C₅₄ alkyl group.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalent group having a cyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, Se, Ge, B, or S as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used herein refers to a divalent group having a cyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, Se, Ge, B, or S as a ring-forming atom, and 1 to 60 carbon atoms. Examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₆-C₁₀ heteroaryl group and the C₆-C₁₀ heteroarylene group each include two or more rings, the rings may be fused to each other.

The term “C₂-C₆₀ alkylheteroaryl group” used herein refers to a C₁-C₅₉ heteroaryl group substituted with at least one C₁-C₅₉ alkyl group.

The term “C₆-C₁₀ aryloxy group” as used herein indicates—OA₁₀₂ (wherein A₁₀₂ is the C₆-C₁₀ aryl group), and the term “C₆-C₁₀ arylthio group” as used herein indicates—SA₁₀₃ (wherein A₁₀₃ is the C₆-C₁₀ aryl group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed to each other, only carbon atoms as ring-forming atoms, and no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) having two or more rings condensed to each other, a heteroatom selected from N, O, P, Si, Se, Ge, B, or S, other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

A substituent of the substituted C₅-C₃₀ carbocyclic group, the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₇-C₆₀ alkylaryl group, the substituted C₆-C₁₀ aryloxy group, the substituted C₆-C₁₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₂-C₆₀ alkyl heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be:

-   -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, or a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, or a C₁-C₆₀ alkoxy group, each unsubstituted or         substituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl         group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl         group, a C₆-C₁₀ aryl group, a C₇-C₆₀ alkyl aryl group, a C₆-C₁₀         aryloxy group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl         group, a C₂-C₆₀ alkyl heteroaryl group, a monovalent         non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),         —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇),         —P(═O)(Q₁₈)(Q₁₉), —P(Q₁₈)(Q₁₉), or any combination thereof,     -   a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a         C₆-C₁₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₁₀ aryloxy         group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl group, a         C₂-C₆₀ alkyl heteroaryl group, a monovalent non-aromatic         condensed polycyclic group, or a monovalent non-aromatic         condensed heteropolycyclic group, each unsubstituted or         substituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀ aryl group, a C₇-C₆₀         alkylaryl group, a C₆-C₁₀ aryloxy group, a C₆-C₁₀ arylthio         group, a C₁-C₆₀ heteroaryl group, a C₂-C₆₀ alkyl heteroaryl         group, a monovalent non-aromatic condensed polycyclic group, a         monovalent non-aromatic condensed heteropolycyclic group,         —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅),         —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), —P(Q₂₈)(Q₂₉), or any combination         thereof;     -   —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅),         —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), or —P(Q₃₈)(Q₃₉); or     -   any combination thereof.

In the present specification, Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independently be hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; an amidino group; a hydrazine group; a hydrazone group; a carboxylic acid group or a salt thereof; a sulfonic acid group or a salt thereof; a phosphoric acid group or a salt thereof; a C₁-C₆₀ alkyl group, unsubstituted or substituted with deuterium, a C₁-C₆₀ alkyl group, a C₆-C₆₀ aryl group, or any combination thereof; a C₂-C₆₀ alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; a C₃-C₁₀ cycloalkyl group; a C₂-C₁₀ heterocycloalkyl group; a C₃-C₁₀ cycloalkenyl group; a C₂-C₁₀ heterocycloalkenyl group; a C₆-C₁₀ aryl group, unsubstituted or substituted with deuterium, a C₁-C₆₀ alkyl group, a C₆-C₁₀ aryl group, or any combination thereof; a C₆-C₁₀ aryloxy group; a C₆-C₁₀ arylthio group; a C₁-C₆₀ heteroaryl group; a monovalent non-aromatic condensed polycyclic group; or a monovalent non-aromatic condensed heteropolycyclic group.

For example, in the present specification, Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each independently be

-   -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, or         —CD₂CDH₂; or     -   an n-propyl group, an isopropyl group, an n-butyl group, a         sec-butyl group, an isobutyl group, a tert-butyl group, an         n-pentyl group, a tert-pentyl group, a neopentyl group, an         isopentyl group, a sec-pentyl group, a 3-pentyl group, a         sec-isopentyl group, a phenyl group, a biphenyl group, or a         naphthyl group, each unsubstituted or substituted with         deuterium, a C₁-C₁₀ alkyl group, a phenyl group, or any         combination thereof.

The term “deuterium-containing C₁-C₆₀ alkyl group (or, deuterium-containing C₁-C₂₀ alkyl group, a deuterium-containing C₂-C₂₀ alkyl group, or the like)” as used herein refers to a C₁-C₆₀ alkyl group substituted with at least one deuterium (or a C₁-C₂₀ alkyl group substituted with at least one deuterium, a C₂-C₂₀ alkyl substituted with at least one deuterium, or the like). For example, the term “the deuterium-containing C₁ alkyl group (that is, a deuterium-containing methyl group)” as used herein includes —CD₃, —CD₂H, and —CDH₂.

The term “deuterium-containing C₃-C₁₀ cycloalkyl group” as used herein refers to a C₃-C₁₀ cycloalkyl group substituted with at least one deuterium. Examples of the “deuterium-containing C₃-C₁₀ cycloalkyl group” are provided in connection with, for example, Formula 10-501.

The terms “fluorinated C₁-C₆₀ alkyl group (or a fluorinated C₁-C₂₀ alkyl group, or the like)”, “fluorinated C₃-C₁₀ cycloalkyl group”, or “fluorinated C₂-C₁₀ heterocycloalkyl group” as used herein refer to a C₁-C₆₀ alkyl group (or, C₁-C₂₀ alkyl group, or the like) substituted with at least one a fluoro group (—F), a C₃-C₁₀ cycloalkyl group substituted with at least one a fluoro group (—F), and a C₂-C₁₀ heterocycloalkyl group substituted with at least one a fluoro group (—F), respectively. For example, the term “the fluorinated C₁ alkyl group (that is, the fluorinated methyl group)” includes —CF₃, —CF₂H, and —CFH₂. The “fluorinated C₁-C₆₀ alkyl group (or the fluorinated C₁-C₂₀ alkyl group, or the like)”, “the fluorinated C₃-C₁₀ cycloalkyl group”, or “the fluorinated C₂-C₁₀ heterocycloalkyl group” may be i) a fully fluorinated C₁-C₆₀ alkyl group (or, fully fluorinated C₁-C₂₀ alkyl group, or the like), a fully fluorinated C₃-C₁₀ cycloalkyl group, or a fully fluorinated C₂-C₁₀ heterocycloalkyl group, each group in which all hydrogen are substituted with a fluoro group, or ii) a partially fluorinated C₁-C₆₀ alkyl group (or, a partially fluorinated C₁-C₂₀ alkyl group, or the like), a partially fluorinated C₃-C₁₀ cycloalkyl group, or a partially fluorinated C₂-C₁₀ heterocycloalkyl group, each group in which some hydrogen are substituted with a fluoro group.

The term “(C₁-C₂₀ alkyl)‘X’ group” as used herein refers to a ‘X’ group substituted with at least one C₁-C₂₀ alkyl group. For example, the term “(C₁-C₂₀ alkyl)C₃-C₁₀ cycloalkyl group” as used herein refers to a C₃-C₁₀ cycloalkyl group substituted with at least one C₁-C₂₀ alkyl group and the term “(C₁-C₂₀ alkyl)phenyl group” as used herein refers to a phenyl group substituted with at least one C₁-C₂₀ alkyl group. An example of a (C₁ alkyl)phenyl group is a toluyl group.

The terms “an azaindole group, an azabenzoborole group, an azabenzophosphole group, an azaindene group, an azabenzosilole group, an azabenzogermole group, an azabenzothiophene group, an azabenzoselenophene group, an azabenzofuran group, an azacarbazole group, an azadibenzoborole group, an azadibenzophosphole group, an azafluorene group, an azadibenzosilole group, an azadibenzogermole group, an azadibenzothiophene group, an azadibenzoselenophene group, an azadibenzofuran group, an azadibenzothiophene 5-oxide group, an aza-9H-fluorene-9-one group, and an azadibenzothiophene 5,5-dioxide group” respectively refer to a heterocyclic group having the same backbone as “an indole group, a benzoborole group, a benzophosphole group, an indene group, a benzosilole group, a benzogermole group, a benzothiophene group, a benzoselenophene group, a benzofuran group, a carbazole group, a dibenzoborole group, a dibenzophosphole group, a fluorene group, a dibenzosilole group, a dibenzogermole group, a dibenzothiophene group, a dibenzoselenophene group, a dibenzofuran group, a dibenzothiophene 5-oxide group, 9H-fluorene-9-one group, and a dibenzothiophene 5,5-dioxide group” in which at least one of the carbon atoms constituting the cyclic groups is substituted with a nitrogen.

In one or more embodiments, a group represented by

in Formula 1 may be a group represented by one of Formulae CY1 to CY88:

In Formulae CY1 to CY88,

-   -   T₄ to T₈ may each independently be:     -   a fluoro group (—F); or     -   a fluorinated C₁-C₂₀ alkyl group, a fluorinated C₃-C₁₀         cycloalkyl group, or a fluorinated C₂-C₁₀ heterocycloalkyl         group, each unsubstituted or substituted with deuterium, a         C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀         heterocycloalkyl group, or any combination thereof;     -   each of R₂, R₄ to R₈ and R_(1a) are the same as described above,         and R₂ and R₄ to R₈ may not be hydrogen,     -   * indicates a binding site to Ir in Formula 1,     -   *″ indicates a binding site to a neighboring atom in Formula 1.

For example, R₂, and R₄ to R₈ in Formulae CY1 to CY88 may each independently be:

-   -   deuterium; or     -   a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀         heterocycloalkyl group, each unsubstituted or substituted with         deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a         C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In one or more embodiments, the group represented by

in Formula 1 may be a group represented by one of Formulae A(1) to A(7):

In Formulae A(1) to A(7),

-   -   Y₂ is C,     -   X₂ is O, S, N(R₂₅), C(R₂₅)(R₂₆), or Si(R₂₅)(R₂₆),     -   each of R₉ to R₁₂ and R₂₁ to R₂₆ are the same as described in         connection with R₂₀,     -   *′ indicates a binding site to Ir in Formula 1, and     -   *″ indicates a binding site to a neighboring atom in Formula 1.

For example, R₉ and R₁₁ in Formula A(1) may each independently be a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In one or more embodiments, R₉ and R₁₁ in Formula A(1) may each independently be a C₁-C₂₀ alkyl group, unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, or any combination thereof.

In one or more embodiments, R₁₀ and R₁₂ in Formula A(1) may each independently be hydrogen or deuterium.

In one or more embodiments, R₉ and R₁₁ in Formula A(1) may be identical to each other.

In one or more embodiments, R₉ and R₁₁ in Formula A(1) may be different from each other.

In one or more embodiments, R₉ and R₁₁ in Formula A(1) may be different from each other, and the number of carbons included in R₁₁ may be greater than the number of carbons included in R₉.

In one or more embodiments, i) at least one of R₉ to R₁₂ in Formula A(1), ii) R₁₁, R₁₂, one of R₂₁ to R₂₆, or any combination thereof in Formulae A(2) and A(3), iii) R₉, R₁₂, one of R₂₁ to R₂₆, or any combination thereof in Formulae A(4) and A(5), and iv) R₉, R₁₀, one of R₂₁ to R₂₆, or any combination thereof in Formulae A(6) and A(7), may each independently be a deuterium-containing C₁-C₂₀ alkyl group, a deuterium-containing C₃-C₁₀ cycloalkyl group, or a deuterium-containing C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In one or more embodiments, at least one of R₉ and R₁₁ in Formula A(1) (for example, R₉ and R₁₁ in Formula A(1)) may each independently be a deuterium-containing C₁-C₂₀ alkyl group, a deuterium-containing C₃-C₁₀ cycloalkyl group, or a deuterium-containing C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.

In one or more embodiments, the group represented by

in Formula 1 may be a group represented by Formula A(1) or A(5).

In one or more embodiments, R₁₄ and R₁₆ in Formula 1 may not be hydrogen.

For example, R₁₃, R₁₄, R₁₆, and R₁₇ in Formula 1 may not be hydrogen.

In one or more embodiments, each of R₁₃, R₁₄, R₁₆ and R₁₇ in Formula 1 may include at least one carbon.

In one or more embodiments, in Formula 1, i) R₁₃ and R₁₇ may each independently be hydrogen or deuterium, and R₁₄ and R₁₆ may each independently be a C₁-C₂₀ alkyl group, unsubstituted or substituted with at least one deuterium.

In one or more embodiments, in Formula 1, i) R₁₃ and R₁₇ may each independently be hydrogen or deuterium, and R₁₄ and R₁₆ may each independently a C₂-C₂₀ alkyl group, unsubstituted or substituted with at least one deuterium.

In one or more embodiments, R₁₃, R₁₄, R₁₆ and R₁₇ in Formula 1 may each independently be a C₁-C₂₀ alkyl group, unsubstituted or substituted with at least one deuterium.

In one or more embodiments, R₁₃, R₁₄, R₁₆ and R₁₇ in Formula 1 may each independently a C₂-C₂₀ alkyl group, unsubstituted or substituted with at least one deuterium.

In one or more embodiments, the number of carbons included in the group represented by *—C(R₁₃)(R₁₄)(R₁₉) in Formula 1 may be 5 or more, and/or the number of carbons included in the group represented by *—C(R₁₆)(R₁₇)(R₁₈) in Formula 1 may be 5 or more.

In one or more embodiments, R₁₃, R₁₄, and R₁₉ of the group represented by *—C(R₁₃)(R₁₄)(R₁₉) in Formula 1 may be linked to each other to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a). That is, the group represented by *—C(R₁₃)(R₁₄)(R₁₉) in Formula 1 may be a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a) (for example, an adamantane group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.1]heptane group (a norbornane group), a bicyclo[2.2.2]octane group, a cyclopentane group, a cyclohexane group, or a cyclohexene group, each unsubstituted or substituted with at least one R_(1a)).

In one or more embodiments, R₁₆, R₁₇ and R₁₈ of the group represented by *—C(R₁₆)(R₁₇)(R₁₈) in Formula 1 may be linked to each other to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a). That is, the group represented by *—C(R₁₆)(R₁₇)(R₁₈) in Formula 1 may be a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a) (for example, an adamantane group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.1]heptane group (a norbornane group), a bicyclo[2.2.2]octane group, a cyclopentane group, a cyclohexane group, or a cyclohexene group, each unsubstituted or substituted with at least one R_(1a)).

For example, the organometallic compound may be at least one of Compounds 1 to 38 below, but embodiments of the present disclosure are not limited thereto.

TMS in Compound 1 to 38 is a trimethylsilyl group, and TMG is a trimethylgermyl group.

In an organometallic compound represented by Formula 1, 1) ring A₁ (see Formula 1′) is, as illustrated in Formula 1, a condensed cyclic group in which two benzene groups are condensed with one pyridine group, and 2) at least one of R₁ to R₈ includes at least one a fluoro group (—F). Accordingly, the transition dipole moment of the organometallic compounds may be increased, and the conjugation length of the organometallic compounds is relatively increased and structural rigidity thereof is increased, leading to a decrease in non-radiative transition. Thus, an electronic device, for example, an organic light-emitting device, including the organometallic compound represented by Formula 1 may have high quantum efficiency (EQE), and thus, may have high luminescence efficiency.

In one or more embodiments, R₁₈ and R₁₉ in Formula 1 may each independently be a substituted or unsubstituted C₂-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group. That is, R₁₈ and R₁₉ in Formula 1 may each have two or more carbons. Therefore, an electron donating capability of Ligand 2 (see Formula 1′) in Formula 1 is improved, and thus, an interaction between Ligand 1 and Ligand 2 in Formula 1 may be enhanced. Thus, the organometallic compound represented by Formula 1 may have improved luminescent transition characteristics, improved optical orientation characteristics, and improved structural rigidity. Accordingly, an electronic device, for example, an organic light-emitting device, including the organometallic compound represented by Formula 1 may have high luminescence efficiency and a long lifespan.

Furthermore, since R₂₀ in the organometallic compound represented by Formula 1 includes neither a fluoro group (—F) nor a cyano group, the organometallic compound represented by Formula 1 may emit light having high color purity (for example, light having a relatively narrow full width at half maximum (FWHM) in the photoluminescent spectrum or electroluminescent spectrum).

In one or more embodiments, the FWHM of the emission peak of the photoluminescent spectrum or electroluminescent spectrum of the organometallic compound may be 64 nm or less. For example, the FWHM of the emission peak of the photoluminescent spectrum or electroluminescent spectrum of the organometallic compound may be from about 45 nm to about 64 nm, about 45 nm to about 59 nm, about 45 nm to about 55 nm or about 50 nm to about 55 nm.

In one or more embodiments, the maximum emission wavelength (emission peak wavelength, λ_(max)) of the emission peak of the photoluminescent spectrum or electroluminescent spectrum of the organometallic compound may be from about 615 nm to about 640 nm. In one or more embodiments, the maximum emission wavelength (emission peak wavelength, λ_(max)) of the emission peak of the photoluminescent spectrum or electroluminescent spectrum of the organometallic compound may be from about 615 nm to about 630 nm or about 620 nm to about 630 nm.

The horizontal orientation ratio of the transition dipole moment of the organometallic compound represented by Formula 1 may be from about 90% to about 100%.

For example, the horizontal orientation ratio of the transition dipole moment of the organometallic compound may be, for example, from about 90% to about 100%, from about 91% to about 100%, from about 92% to about 100%, from about 93% to about 100%, from about 94% to about 100%, from about 95% to about 100%, from about 96% to about 100%, from about 97% to about 100%, from about 98% to about 100%, from about 99% to about 100%, or about 100%.

The horizontal orientation ratio of the transition dipole moment may be evaluated by using an angle-dependent photoluminescence (PL) measurement apparatus. The angle-dependent PL measurement apparatus may be understood by referring to, for example, the description of the angle-dependent PL measurement apparatus disclosed in Korean application No. 2013-0150834. Korean application No. 2013-0150834 is incorporated herein.

As described above, since the horizontal orientation ratio of the transition dipole moment of the organometallic compound is high, when an organic light-emitting device including the organometallic compound is driven, an electric field may be emitted in a substantially parallel to a film including the organometallic compound, and thus, optical loss caused by a waveguide mode and/or a surface plasmon polariton mode may be reduced. Due to an external extraction efficiency of the electronic device emitting light (that is, an efficiency of light extracted to the outside from the electronic device (for example, an organic light-emitting device) including a film including the organometallic compound (for example, an emission layer to be described)) by such a mechanism, an electronic device, for example, an organic light-emitting device, including the organometallic compound may have high luminescence efficiency.

The photoluminescence quantum yield of the organometallic compound represented by Formula 1 in film may be from about 90% to about 100%. For example, the PLQY of the organometallic compound in a film may be from about 91% to about 100%, from about 92% to about 100%, from about 93% to about 100%, from about 94% to about 100%, from about 95% to about 100%, from about 96% to about 100%, from about 97% to about 100%, from about 98% to about 100%, or from about 99% to about 100%, or about 100%.

In one or more embodiments, the PLQY of the organometallic compound in a film may be from about 95% to about 99%, from about 96% to about 99%, from about 97% to about 99%, or from about 98% to about 99%.

The method of measuring the PLQY in film may be understood by referring to Evaluation Example 1.

Synthesis methods of the organometallic compound represented by Formula 1 may be understood by one of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect provides an organic light-emitting device that includes: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode and including an emission layer, and the organic layer includes at least one organometallic compounds represented by Formula 1.

Since the organic light-emitting device includes an organic layer including the organometallic compound represented by Formula 1 described above, excellent characteristics may be obtained in terms of the driving voltage, the external quantum efficiency, a relatively narrow FWHM of an electroluminescence (EL) spectrum emission peak and a lifespan.

The organometallic compound of Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, an amount of the organometallic compound represented by Formula 1 in the emission layer is smaller than an amount of the host).

In one or more embodiments, the emission layer may emit red light.

The expression “(an organic layer) includes at least one organometallic compound” used herein may include a case in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and a case in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this regard, Compound 1 may exist in an emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may exist in an identical layer (for example, Compound 1 and Compound 2 all may exist in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode, or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In one or more embodiments, in the organic light-emitting device, the first electrode is an anode, and the second electrode is a cathode, and the organic layer further includes a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode, and the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and the electron transport region includes a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

FIGURE is a schematic view of an organic light-emitting device 10 according to one embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with FIGURE. The organic light-emitting device 10 includes a first electrode 11, an organic layer 15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally located under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate that is used in general organic light-emitting devices may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

In one or more embodiments, the first electrode 11 may be formed by depositing or sputtering a material for forming the first electrode 11 on the substrate. The first electrode 11 may be an anode. The material for forming the first electrode 11 may include a material with a high work function to facilitate hole injection. The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode 11 may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), or zinc oxide (ZnO). In one or more embodiments, the material for forming the first electrode 11 may be metal, such as magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag).

The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 11 may have a three-layered structure of ITO/Ag/ITO.

The organic layer 15 is located on the first electrode 11.

The organic layer 15 may include a hole transport region, an emission layer, and an electron transport region.

The hole transport region may be between the first electrode 11 and the emission layer.

The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof.

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode 11.

When the hole transport region includes a hole injection layer (HIL), the hole injection layer may be formed on the first electrode 11 by using one or more suitable methods, for example, vacuum deposition, spin coating, casting, and/or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary according to a material that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100° C. to about 500° C. a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition rate of about 0.01 Å/sec to about 100 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary according to the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 rpm to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

The hole transport region may include m-MTDATA, TDATA, 2-TNATA, NPB, 3-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, a compound represented by Formula 202 below, or any combination thereof:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be a phenylene group, a pentalenylene group, an indenylene group, a naphthylene group, an azulenylene group, a heptalenylene group, an acenaphthylene group, a fluorenylene group, a phenalenylene group, a phenanthrenylene group, an anthracenylene group, a fluoranthenylene group, a triphenylenylene group, a pyrenylene group, a chrysenylenylene group, a naphthacenylene group, a picenylene group, a perylenylene group, or a pentacenylene group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, or any combination thereof.

The designations xa and xb in Formula 201 may each independently be an integer from 0 to 5, or 0, 1 or 2. For example, xa may be 1 and xb may be 0, but xa and xb are not limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉ and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 may each independently be:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid or a salt         thereof, a sulfonic acid or a salt thereof, a phosphoric acid or         a salt thereof, a C₁-C₁₀ alkyl group (for example, a methyl         group, an ethyl group, a propyl group, a butyl group, a pentyl         group, or a hexyl group), or a C₁-C₁₀ alkoxy group (for example,         a methoxy group, an ethoxy group, a propoxy group, a butoxy         group, or a pentoxy group);     -   a C₁-C₁₀ alkyl group or a C₁-C₁₀ alkoxy group, each         unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, or         any combination thereof; or     -   a phenyl group, a naphthyl group, an anthracenyl group, a         fluorenyl group, or a pyrenyl group, each unsubstituted or         substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group,         a cyano group, a nitro group, an amino group, an amidino group,         a hydrazine group, a hydrazone group, a carboxylic acid or a         salt thereof, a sulfonic acid or a salt thereof, a phosphoric         acid or a salt thereof, a C₁-C₁₀ alkyl group, or a C₁-C₁₀ alkoxy         group, or any combination thereof.

R₁₀₉ in Formula 201 may be a phenyl group, a naphthyl group, an anthracenyl group, or a pyridinyl group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyridinyl group, or any combination thereof.

In one or more embodiments, the compound represented by Formula 201 may be represented by Formula 201A:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood by referring to the description provided herein.

For example, the hole transport region may include one of Compounds HT1 to HT21 or any combination thereof:

The thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, the thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å, and a thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, for example, about 100 Å to about 1,500 Å. When the thicknesses of the hole transport region, the hole injection layer and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant. The p-dopant may be a quinone derivative, a metal oxide, a cyano group-containing compound, or any combination thereof, but embodiments of the present disclosure are not limited thereto. Examples of the p-dopant are a quinone derivative, such as tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinone dimethane (F4-TCNQ), or F6-TCNNQ; a metal oxide, such as a tungsten oxide or a molybdenum oxide; a cyano group-containing compound, such as Compound HT-D1 below; or any combination thereof.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be a material for the hole transport region described above, a material for a host to be explained later, or any combination thereof. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained later, Compound H21, or any combination thereof.

Then, an emission layer (EML) may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer although the deposition or coating conditions may vary according to a material that is used to form the hole transport layer.

The emission layer may include a host and a dopant, and the dopant may include an organometallic compound represented by Formula 1 described herein.

The host may include TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, Compound H51, Compound 52, or any combination thereof:

When the organic light-emitting device is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and/or a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. When the thickness of the emission layer is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Then, an electron transport region may be located on the emission layer.

The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, but the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, and BAlq.

In one or more embodiments, the hole blocking layer may include the host, a material for forming an electron transport layer to be described later, a material for forming an electron injection layer to be described later, or any combination thereof.

The thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 600 Å. When the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have excellent hole blocking characteristics without a substantial increase in driving voltage.

The electron transport layer may include BCP, Bphen, TPBi, Alq₃, Balq, TAZ, NTAZ, or any combination thereof:

In one or more embodiments, the electron transport layer may include one of Compounds ET1 to ET25 or any combination thereof:

The thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. When the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

Also, the electron transport layer may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 or ET-D2.

The electron transport region may include an electron injection layer (EIL) that promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include LiF, NaCl, CsF, Li₂O, BaO, or any combination thereof.

The thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, and, for example, about 3 Å to about 90 Å. When the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

The second electrode 19 may be located on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be metal, an alloy, an electrically conductive compound, or any combination thereof, which have a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be formed as the material for forming the second electrode 19. To manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described with reference to FIGURE, but embodiments of the present disclosure are not limited thereto.

Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Example and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of A used was identical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1 (Compound 4)

Synthesis of Intermediate L4-4

5 g (20.9 mmol) of 2-chloro-4-iodopyridine was mixed with 50 ml of anhydrous THF, and 12.5 ml (25 mmol) of 2.0 M lithium diisopropylamide (in THF) was slowly added dropwise thereto at a temperature of −78° C. After about 3 hours, 2.5 ml (32 mmol) of ethyl formate was slowly added dropwise thereto, and then, the resultant mixture was stirred for 18 hours at room temperature. Water and ethyl acetate were added to the reaction mixture to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 2.2 g (yield of 40%) of Intermediate L4-4.

LC-MS m/z=769.48 (M+H)⁺

Synthesis of Intermediate L4-3

1.9 g (7.2 mmol) of Intermediate L4-4 was mixed with 60 ml of acetonitrile and 15 ml of water, and then, 0.4 g (0.5 mmol) of PdCl₂(PPh₃)₂, 1.0 g (7.2 mmol) of 3-fluorophenylboronic acid, and 2.5 g (18.0 mmol) of K₂CO₃ were added thereto, and then, the mixture was heated while refluxing at a temperature of 80° C. for 18 hours. The reaction mixture was concentrated under reduced pressure, and dichloromethane and water were added thereto to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 1.4 g (yield 78%) of Intermediate L4-3.

LC-MS m/z=236 (M+H)⁺

Synthesis of Intermediate L4-2

5.4 g (15.8 mmol) of (methoxymethyl)triphenylphosphonium chloride was mixed with 50 ml of anhydrous ether, and then, 16 ml of 1.0 M potassium tert-butoxide solution (in THF) was added dropwise thereto, and the mixture was stirred at room temperature for about 1 hour. Thereafter, 1.5 g (6.3 mmol) of Intermediate L4-3 mixed with 30 ml of anhydrous THF was slowly added dropwise thereto, and the resultant mixture was stirred at room temperature for 18 hours. Water and ethyl acetate were added to the reaction mixture to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 1.6 g (yield of 95%) of Intermediate L4-2.

LC-MS m/z=264 (M+H)⁺

Synthesis of Intermediate L4-1

1.4 g (5.1 mmol) of Intermediate L4-2 was mixed with 40 ml of dichloro methane, and 3.0 ml of methanesulfonic acid was slowly added dropwise thereto, and then, the resultant mixture was stirred at room temperature for about 18 hours. A saturated sodium bicarbonate aqueous solution was added to the reaction mixture to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 1.0 g (yield of 90%) of Intermediate L4-1.

LC-MS m/z=232 (M+H)⁺

Synthesis of Intermediate L4

1.0 g (4.1 mmol) of Intermediate L4-1 was mixed with 40 ml of THF and 10 ml of water, 0.9 g (6.2 mmol) of 3,5-dimethylphenylboronic acid, 0.09 g (0.4 mmol) of Pd(OAc)₂, 0.35 g (0.82 mmol) of Sphos, and 1.4 g (10.3 mmol) of K₂CO₃ were added thereto, and the mixture was heated while refluxing. Ethyl acetate and water were added to the reaction mixture to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 1.1 g (yield of 85%) of Intermediate L4.

LC-MS m/z=302 (M+H)⁺

Synthesis of Intermediate L4 Dimer

40 mL of ethoxyethanol and 15 mL of distilled water were mixed with 1.05 g (3.4 mmol) of Intermediate L4 and 0.6 g (1.6 mmol) of iridium chloride, and then, the mixture was heated while refluxing for 24 hours. The temperature of the reaction mixture was decreased to room temperature to obtain a solid product, which was then filtered and washed sequentially by using water, methanol, and hexane in the stated order. The resultant solid dried in a vacuum oven to obtain 1.1 g of Intermediate L4 Dimer.

Synthesis of Compound 4

1.0 g (0.63 mmol) of Intermediate L4 Dimer, 0.9 g (4.5 mmol) of 3,7-diethyl-3,7-dimethylnonane-4,6-dione, and 0.48 g (4.5 mmol) of Na₂CO₃ were mixed with 40 mL of ethoxyethanol, and then, the mixture was stirred for 24 hours at a temperature of 90° C. The reaction mixture was cooled to room temperature to obtain a solid product, which was then filtered and purified by liquid chromatography to obtain 1.0 g (yield of 80%) of Compound 4.

LC-MS m/z=1035 (M+H)⁺

Synthesis Example 2 (Compound 1)

Synthesis of Intermediate L1-2

6.0 g (23.7 mmol) of 2-chloro-4-iodo-3-methylpyridine was mixed with 80 ml of acetonitrile and 20 ml of water, and then, 1.2 g (1.6 mmol) of PdCl₂(PPh₃)₂, 4.4 g (26.1 mmol) of (3-fluoro-2-formylphenyl)boronic acid, and 8.2 g (59.2 mmol) of K₂CO₃ were added thereto, and the resultant mixture was heated while refluxing at a temperature of 80° C. for 18 hours. The reaction mixture was concentrated under reduced pressure, and ethyl acetate and water were added thereto to extract an organic layer, which was then dried by using magnesium sulfate, followed by distillation under reduced pressure and purification using liquid chromatography to obtain 5.0 g (yield of 85%) of Intermediate L1-2.

LC-MS m/z=250 (M+H)⁺

Synthesis of Intermediate L1-1

4.0 g (16.0 mmol) of Intermediate L1-2 was dissolved in 150 ml of anhydrous N,N-dimethylformamide, and then, 19 ml (19.2 mmol) of 1.0 M potassium tert-butoxide solution in THF was slowly added dropwise thereto at room temperature, and then, the reaction mixture was heated at a temperature of 80° C. for 6 hours. Once the reaction was completed, ethyl acetate and water were added thereto to extract an organic layer, which was then dried by using magnesium sulfate. The reaction mixture was filtered, concentrated under reduced pressure, and then, purified by liquid chromatography to obtain 1.3 g (yield of 35%) of Intermediate 1-1.

LC-MS m/z=232 (M+H)⁺

Synthesis of Intermediate L1

1.4 g (yield of 85%) of Intermediate L1 was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L1-1 was used instead of Intermediate L4-1.

LC-MS m/z=303 (M+H)⁺

Synthesis of Intermediate L1 Dimer

Intermediate L1 Dimer was prepared in the same manner as used to synthesize L4 Dimer of Synthesis Example 1, except that Intermediate L1 was used instead of Intermediate L4.

Synthesis of Compound 1

0.6 g (yield of 47%) of Compound 1 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L1 Dimer was used instead of Intermediate L4 Dimer.

LC-MS m/z=1035 (M+H)⁺

Synthesis Example 3 (Compound 6)

Synthesis of Intermediate L6-3

2.5 g (yield of 73%) of Intermediate L6-3 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that 3-(trifluoromethyl)phenylboronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=286 (M+H)⁺

Synthesis of Intermediate L6-2

2.7 g (yield of 99%) of Intermediate L6-2 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate L6-3 was used instead of Intermediate L4-3.

LC-MS m/z=314 (M+H)⁺

Synthesis of Intermediate L6-1

1.1 g (yield of 45%) of Intermediate L6-1 was prepared in the same manner as used to synthesize Intermediate L4-1 of Synthesis Example 1, except that Intermediate L6-2 was used instead of Intermediate L4-2.

LC-MS m/z=282 (M+H)⁺

Synthesis of Intermediate L6

1.1 g of Intermediate L6 (yield of 80%) was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L6-1 was used instead of Intermediate L4-1.

LC-MS m/z=352 (M+H)⁺

Synthesis of Intermediate L6 Dimer

Intermediate L6 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L6 was used instead of Intermediate L4.

Synthesis of Compound 6

0.7 g (yield of 43%) of Compound 6 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L6 Dimer and 3,3,7,7-tetramethylnonane-4,6-dione were used instead of Intermediate L4 Dimer and 3,7-diethyl-3,7-dimethylnonane-4,6-dione, respectively.

LC-MS m/z=1107 (M+H)⁺

Synthesis Example 4 (Compound 7)

Synthesis of Intermediate L7-3

1.8 g (yield 70%) of Intermediate L7-3 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that 3-(trifluoromethyl)-4-methylphenylboronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=300 (M+H)⁺

Synthesis of Intermediate L7-2

1.8 g (yield of 95%) of Intermediate L7-2 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate 17-3 was used instead of Intermediate L4-3.

LC-MS m/z=328 (M+H)⁺

Synthesis of Intermediate L7-1

0.8 g (yield of 40%) of Intermediate L7-1 was prepared in the same manner as used to synthesize Intermediate L7-1 of Synthesis Example 1, except that Intermediate L7-2 was used instead of Intermediate L4-2.

LC-MS m/z=296 (M+H)⁺

Synthesis of Intermediate L7

0.8 g (yield of 90%) of Intermediate L7 was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L7-1 was used instead of Intermediate L4-1.

LC-MS m/z=366 (M+H)⁺

Synthesis of Intermediate L7 Dimer

Intermediate L7 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L7 was used instead of Intermediate L4.

Synthesis of Compound 7

0.6 g (yield of 46%) of Compound 7 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L7 Dimer and 3,7-diethylnonane-4,6-dione were used instead of Intermediate L4 Dimer and 3,7-diethyl-3,7-dimethylnonane-4,6-dione, respectively.

LC-MS m/z=1135 (M+H)⁺

Synthesis Example 5 (Compound 9)

Synthesis of Intermediate L9-3

2.1 g (yield of 80%) of Intermediate L9-3 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that 3,5-difluorophenylboronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=268 (M+H)⁺

Synthesis of Intermediate L9-2

2.2 g (yield of 99%) of Intermediate L9-2 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate L9-3 was used instead of Intermediate L4-3.

LC-MS m/z=282 (M+H)⁺

Synthesis of Intermediate L9-1

0.8 g (yield of 40%) of Intermediate L9-1 was prepared in the same manner as used to synthesize Intermediate L4-1 of Synthesis Example 1, except that Intermediate L9-2 was used instead of Intermediate L4-2.

LC-MS m/z=250 (M+H)⁺

Synthesis of Intermediate L9

0.9 g of Intermediate L9 (yield of 87%) was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L9-1 was used instead of Intermediate L4-1.

LC-MS m/z=320 (M+H)⁺

Synthesis of Intermediate L9 Dimer

Intermediate L9 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L9 was used instead of Intermediate L4.

Synthesis of Compound 9

0.7 g (yield of 48%) of Compound 9 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L9 Dimer and 3,3,7,7-tetramethylnonane-4,6-dione were used instead of Intermediate L4 Dimer and 3,7-diethyl-3,7-dimethylnonane-4,6-dione, respectively.

LC-MS m/z=1043 (M+H)⁺

Synthesis Example 6 (Compound 16)

Synthesis of Intermediate L16-3

2.5 g (yield of 72%) of Intermediate L16-3 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that 2,5-difluorophenylboronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=268 (M+H)⁺

Synthesis of Intermediate L16-2

2.6 g (yield of 98%) of Intermediate L16-2 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate L16-3 was used instead of Intermediate L4-3.

LC-MS m/z=282 (M+H)⁺

Synthesis of Intermediate L16-1

0.9 g (yield of 38%) Intermediate L16-1 was prepared in the same manner as used to synthesize Intermediate L4-1 of Synthesis Example 1, except that Intermediate L16-2 was used instead of Intermediate L4-2.

LC-MS m/z=250 (M+H)⁺

Synthesis of Intermediate L16

0.8 g of Intermediate L16 (yield of 75%) was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L16-1 was used instead of Intermediate L4-1.

LC-MS m/z=320 (M+H)⁺

Synthesis of Intermediate L16 Dimer

Intermediate L16 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L16 was used instead of Intermediate L4.

Synthesis of Compound 16

0.6 g (yield of 40%) of Compound 16 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L16 Dimer was used instead of Intermediate L4 Dimer.

LC-MS m/z=1071 (M+H)⁺

Synthesis Example 7 (Compound 18)

Synthesis of Intermediate L18-2

2.6 g (yield of 80%) of Intermediate L18-2 was prepared in the same manner as used to synthesize Intermediate L1-2 of Synthesis Example 2, except that 2-fluoro-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3-(trimethylsilyl)benzaldehyde was used instead of 3-fluoro-2-formylphenyl)boronic acid.

LC-MS m/z=322 (M+H)⁺

Synthesis of Intermediate L18-1

0.7 g (yield of 30%) of Intermediate L18-1 was prepared in the same manner as used to synthesize Intermediate L1-1 of Synthesis Example 2, except that Intermediate L18-2 was used instead of Intermediate L1-2.

LC-MS m/z=304 (M+H)⁺

Synthesis of Intermediate L18

0.6 g (yield of 73%) of Intermediate L18 was prepared in the same manner as used to synthesize Intermediate L1 of Synthesis Example 2, except that Intermediate L18-1 was used instead of Intermediate L1-1.

LC-MS m/z=374 (M+H)⁺

Synthesis of Intermediate L18 Dimer

Intermediate L18 Dimer was prepared in the same manner as used to synthesize Intermediate L1 Dimer of Synthesis Example 2, except that Intermediate L18 was used instead of Intermediate L1.

Synthesis of Compound 18

0.4 g (yield of 40%) of Compound 18 was prepared in the same manner as used to synthesize Compound 1 of Synthesis Example 2, except that Intermediate L18 Dimer was used instead of Intermediate L1 Dimer.

LC-MS m/z=1180 (M+H)⁺

Synthesis Example 8 (Compound 23)

Synthesis of Intermediate L23

1.2 g (3.7 mmol) of Intermediate L9 was dissolved in 60 ml of anhydrous tetrahydrofuran (THF), and then, 2.4 ml (3.7 mmol) of 1.6 M BuLi solution in hexane was slowly added thereto at a temperature of −78° C. After about one hour, 0.7 ml (5.6 mmol) of chlorotrimethylgermane was slowly added dropwise thereto and stirred for 18 hours at room temperature. Once the reaction was completed, 50 ml of ethyl acetate and a saturated sodium thiosulfate aqueous solution were added thereto to extract an organic layer, which was then dried by using magnesium sulfate and distilled under reduced pressure. The crude product was purified by liquid chromatography to obtain 1.2 g (yield of 76%) of Intermediate L23.

LC-MS m/z=438 (M+H)⁺

Synthesis of Intermediate L23 Dimer

Intermediate L23 Dimer was prepared in the same manner as used to synthesize Intermediate L6 Dimer of Synthesis Example 3, except that Intermediate L23 was used instead of Intermediate L6.

Synthesis of Compound 23

0.8 g (yield of 45%) of Compound 23 was prepared in the same manner as used to synthesize Compound 6 of Synthesis Example 3, except that Intermediate L23 Dimer was used instead of Intermediate L6 Dimer.

LC-MS m/z=1279 (M+H)⁺

Synthesis Example 9 (Compound 28)

Synthesis of Intermediate L28-6

6.2 g (yield of 71%) of Intermediate L28-6 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that 3-bromo-5-(trifluoromethyl)phenyl)boronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=364 (M+H)⁺

Synthesis of Intermediate L28-5

6.5 g (yield of 98%) of Intermediate L28-5 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate L28-6 was used instead of Intermediate L4-3.

LC-MS m/z=392 (M+H)⁺

Synthesis of Intermediate L28-4

2.1 g (yield of 35%) of Intermediate L28-4 was prepared in the same manner as used to synthesize Intermediate L4-1 of Synthesis Example 1, except that Intermediate L28-5 was used instead of Intermediate L4-2.

LC-MS m/z=360 (M+H)⁺

Synthesis of Intermediate L28-3

2.1 g (5.9 mmol) of Intermediate L28-4 was mixed with 120 ml of acetonitrile, and then, 1.1 ml (8.9 mmol) of chlorotrimethylsilane and 1.3 g (8.9 mmol) of NaI were added thereto and then heated while refluxing for 36 hours at a temperature of 90° C. Once the reaction was completed, 60 ml of ethyl acetate and a saturated sodium thiosulfate aqueous solution were added thereto to extract an organic layer, which was then dried by using magnesium sulfate and distilled under reduced pressure. The crude product was purified by liquid chromatography to obtain 2.3 g (yield of 87%) of Intermediate L28-3.

LC-MS m/z=452 (M+H)⁺

Synthesis of Intermediate L28-2

1.8 g (yield of 80%) Intermediate L28-2 was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L28-3 was used instead of Intermediate L4-1.

LC-MS m/z=430 (M+H)⁺

Synthesis of Intermediate L28-1

1.8 g (4.2 mmol) of Intermediate L28-2 was mixed with 60 ml of tetrahydrofuran (THF) and 15 ml of water, and then, 0.9 g (5.0 mmol) of 4,4,5,5-tetramethyl-2-(prop-1-en-2-yl)-1,3,2-dioxaborolane, 0.1 g (0.4 mmol) of Pd(OAc)₂, 0.3 g (0.8 mmol) of Sphos, and 1.5 g (10.5 mmol) of K₂CO₃ were added thereto, and heated while refluxing at a temperature of 80° C. for 18 hours. When the reaction was completed, an organic layer, obtained by performing an extraction process on the reaction mixture by using 50 ml of ethyl acetate, was dried by using magnesium sulfate, distilled under reduced pressure, and purified by liquid chromatography to obtain 1.2 g (yield of 75%) of Intermediate L28-1.

LC-MS m/z=392 (M+H)⁺

Synthesis of Intermediate L28

1.2 g (3.1 mmol) of Intermediate L28-1 was mixed with 60 ml of ethanol, and then, 0.1 g (10 wt %) of Pd/C was added thereto, and hydrogen was injected thereto, followed by 18 hours of mixing at room temperature. When the reaction was completed, the reaction mixture was allowed to pass through a celite pad and then concentrated under reduced pressure, and then, purified by liquid chromatography to obtain 1.1 g (yield of 90%) of Intermediate L28.

LC-MS m/z=394 (M+H)⁺

Synthesis of Intermediate L28 Dimer

Intermediate L28 Dimer was prepared in the same manner as used to synthesize Intermediate L1 Dimer of Synthesis Example 2, except that Intermediate L28 was used instead of Intermediate L1.

Synthesis of Compound 28

0.6 g (yield of 38%) of Compound 28 was prepared in the same manner as used to synthesize Compound 2 of Synthesis Example 1, except that Intermediate L28 Dimer was used instead of Intermediate L1 Dimer.

LC-MS m/z=1219 (M+H)⁺

Synthesis Example 10 (Compound 20)

Synthesis of Intermediate L20-3

1.8 g (yield of 80%) of Intermediate L20-3 was prepared in the same manner as used to synthesize Intermediate L4-3 of Synthesis Example 1, except that (3,5-difluoro-4-methylphenyl)boronic acid was used instead of 3-fluorophenylboronic acid.

LC-MS m/z=268 (M+H)⁺

Synthesis of Intermediate L20-2

1.9 g (yield of 97%) of Intermediate L20-2 was prepared in the same manner as used to synthesize Intermediate L4-2 of Synthesis Example 1, except that Intermediate L20-3 was used instead of Intermediate L4-3.

LC-MS m/z=296 (M+H)⁺

Synthesis of Intermediate L20-1

0.8 g (yield of 47%) of Intermediate L20-1 was prepared in the same manner as used to synthesize Intermediate L4-1 of Synthesis Example 1, except that Intermediate L20-2 was used instead of Intermediate L4-2.

LC-MS m/z=264 (M+H)⁺

Synthesis of Intermediate L20

0.8 g (yield of 84%) of Intermediate L20 was prepared in the same manner as used to synthesize Intermediate L4 of Synthesis Example 1, except that Intermediate L20-1 was used instead of Intermediate L4-1.

LC-MS m/z=333 (M+H)⁺

Synthesis of Intermediate L20 Dimer

Intermediate L20 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L20 was used instead of Intermediate L4.

Synthesis of Compound 20

0.5 g (yield of 40%) of Compound 20 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L20 Dimer was used instead of Intermediate L4 Dimer.

LC-MS m/z=1099 (M+H)⁺

Synthesis Example 11 (Compound 23)

Synthesis of Intermediate L34

1.0 g (yield of 78%) of Intermediate L34 was prepared in the same manner as used to synthesize Intermediate L1 of Synthesis Example 2, except that (3,5-bis(methyl-d3)phenyl)boronic acid was used instead of 3,5-Dimethylphenylboronic acid.

LC-MS m/z=308 (M+H)⁺

Synthesis of Intermediate L34 Dimer

Intermediate L34 Dimer was prepared in the same manner as used to synthesize Intermediate L4 Dimer of Synthesis Example 1, except that Intermediate L34 was used instead of Intermediate L4.

Synthesis of Compound 34

0.8 g (yield of 52%) of Compound 34 was prepared in the same manner as used to synthesize Compound 4 of Synthesis Example 1, except that Intermediate L34 Dimer was used instead of Intermediate L4 Dimer.

LC-MS m/z=1045 (M+H)⁺

Evaluation Example 1: Evaluation of Photoluminescence Quantum Yields (PLQY)

Compound H52 and Compound 4 were co-deposited at a vacuum pressure of 10⁻⁷ torr and at a weight ratio of 98:2 to produce a 40 nm-thick film.

The PLQY of Compound 4 in film was evaluated by using a Hamamatsu Photonics absolute PL quantum yield measurement system equipped with a xenon light source, a monochromator, a photonic multichannel analyzer, and an integrating sphere, and using PLQY measurement software (Hamamatsu Photonics, Ltd., Shizuoka, Japan). The results thereof are shown in Table 1.

The PLQY of each of Compounds 1, 6, 7, 9, 16, 18, 23, 28, 34, A1, B1, and C1 were performed, and the results thereof are shown in Table 1.

TABLE 1 Compound No. PLQY in film (%)  4 99  1 99  6 99  7 98  9 99 16 97 18 97 23 98 28 99 34 99 A1 90 B1 88 C1 90

From Table 1, it was confirmed that Compounds 4, 1, 6, 7, 9, 16, 18, 23, 28 and 34 showed better PLQY characteristics than Compounds A1, B1, and C1.

Evaluation Example 2: Evaluation of Horizontal Orientation Ratio (Optical Orientation Ratio)

In a vacuum deposition apparatus having a vacuum pressure of 1×10⁻⁷ torr, Compound H52 and Compound 4 were co-deposited on a fused silica layer (thickness of 1 mm) at a weight ratio of 98:2 to form a 40 nm thick film. Then, the film was sealed with glass and glue under a nitrogen atmosphere.

Meanwhile, an angle-dependent PL measuring apparatus having the structure shown in FIG. 3 of KR application 2013-0150834 was prepared. Specific specifications are as follows:

-   -   Excitation-light wavelength: 325 nm     -   Excitation-light source: He—Cd laser, Melles Griot, Inc.     -   Excitation-light irradiation member: optical fiber, diameter of         1 mm, Thorlabs, Inc.     -   Semi-cylindrical prism: fused silica, diameter of 100 mm, and         length of 30 mm,     -   Emitted-light detection member: photomultiplier tube, Acton,         Inc.     -   Polarizer mounted on emitted-light detection member: Linear         polarizer, Thorlabs, Inc.     -   Recording apparatus SpectraSense, Acton, Inc.     -   Excitation-light incident angle: θP=45°, θH=0°     -   Distance from a sample to an emitted-light detection member (or         radius of travel path of emitted-light detection member): 900 mm

Then, the film was fixed on the semi-cylindrical lens and irradiated with a 325 nm laser to emit light. The emitted light was guided to pass through a polarizing film and the p-polarized photoluminescence intensity was measured with respect to light at a Max wavelength of the spectrum of 90 degrees to 0 degree by rotating the semi-cylindrical lens on which the sample is fixed by 1 degree with respect to the axis of the lens by using a charge-coupled device (CCD).

A p-polarized photoluminescence intensity which is shown when each compound has a vertical orientation (first p-polarized photoluminescence intensity), and a p-polarized photoluminescence intensity which is shown when each compound has a horizontal orientation (second p-polarized photoluminescence intensity) were each calculated from at the degree of 0 to the degree of 90. A weighted value where a p-polarized photoluminescence intensity obtained by multiplying each of the first and second p-polarized photoluminescence intensities with a weighted value matches with a measured p-polarized photoluminescence intensity, was identified to measure the horizontal orientation ratio of compounds shown in Table 2. The results thereof are shown in Table 2. In this case, the angle-dependent photoluminescence spectrum was analyzed using a classical dipole model, in which the emission from excitons is regarded as the dissipated power consumed from the oscillating dipole, to evaluate the horizontal orientation ratio with respect to Compound 4.

The horizontal orientation ratio of each of Compounds 1, 6, 7, 9, 16, 18, 23, 28, 34, A1, B1, and C1 were performed, and the results thereof are shown in Table 2.

TABLE 2 Horizontal orientation ratio Co-Deposition Materials (optical orientation ratio) (%) H52 Compound 4 (2 wt %) 91 H52 Compound 1 (2 wt %) 91 H52 Compound 6 (2 wt %) 91 H52 Compound 7 (2 wt %) 93 H52 Compound 9 (2 wt %) 92 H52 Compound 16 (2 wt %) 91 H52 Compound 18 (2 wt %) 93 H52 Compound 23 (2 wt %) 94 H52 Compound 28 (2 wt %) 93 H52 Compound 34 (2 wt %) 91 H52 Compound A1 (2 wt %) 83 H52 Compound B1 (2 wt %) 82 H52 Compound C1 (2 wt %) 88

From Table 2, it was confirmed that Compounds 4, 1, 6, 7, 9, 16, 18, 23, 28 and 34 showed better horizontal orientation ratio characteristics than Compounds A1, B1, and C1.

Example 1

The ITO-patterned glass substrate as an anode was cut into a size of 50 mm×50 mm×0.5 mm, ultrasonically cleaned with isopropyl alcohol and pure water, each for 5 minutes, and then irradiated with ultraviolet light for 30 minutes and cleaned by exposure to ozone. Then, the resultant substrate was mounted on a vacuum deposition apparatus.

HT3 and F6TCNNQ were vacuum co-deposited on the ITO anode at the weight ratio of 98:2 to form a hole injection layer having a thickness of 100 Å, HT3 was vacuum-deposited on the hole injection layer to form a hole transport layer having a thickness of 1350 Å, and then, HT21 was vacuum-deposited on the hole transport layer to form an electron blocking layer having a thickness of 300 Å.

Then, H52 (host) and Compound 4 (dopant) were co-deposited at a weight ratio of 98:2 on the electron blocking layer to form an emission layer having a thickness of 400 Å.

Then, ET3 and ET-D1 were co-deposited at a volume ratio of 50:50 on the emission layer to form an electron transport layer having a thickness of 350 Å, and ET-D1 was vacuum-deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a cathode having a thickness of 1000 Å, thereby completing the manufacture of an organic light-emitting device having the structure of ITO (1500 Å)/HT3+F6TCNNQ (2 wt %) (100 Å)/HT3 (1350 Å)/HT21 (300 Å)/H52+Compound 4 (2 wt %) (400 Å) /ET3+ET-D1 (50%) (350 Å)/ET-D1 (10 Å)/Al (1000 Å).

Examples 2 to 10 and Comparative Examples A1 to C1

Organic light-emitting devices were manufactured in the same manner as in Example 1, except that in forming an emission layer, for use as a dopant, corresponding compounds shown in Table 3 were used instead of Compound 4.

Evaluation Example 3: Evaluation on Characteristics of Organic Light-Emitting Device

The driving voltage, current density, maximum external quantum efficiency (Max EQE), FWHM and maximum emission wavelength (peak emission wavelength) of the EL spectrum (λ_(max)) and lifespan (LT₉₇) of each of the organic light-emitting devices manufactured according to Examples 1 to 10 and Comparative Examples A1 to C1 were evaluated. The results thereof are shown in Tables 3 and 4. This evaluation was perfumed using a current-voltage meter (Keithley 2400) and a luminescence meter (Minolta Cs-1,000A), and the lifespan (LT₉₇) (at 3500 nit) was evaluated for each organic light-emitting device by measuring the amount of time that elapsed until luminescence was reduced to 97% of the initial luminescence of 100%, and expressed as a relative value (%).

TABLE 3 Dopant in Driving Current emission layer voltage density Max EQE FWHM Compound No. (V) (mA/cm²) (%) (nm) Example 1 4 4.2 10 29 50 Example 2 1 4.2 10 29 50 Example 3 6 4.0 10 28 52 Example 4 7 4.0 10 30 52 Example 5 9 3.8 10 31 53 Example 6 16 4.1 10 30 52 Example 7 18 4.0 10 32 51 Example 8 23 3.9 10 31 50 Example 9 28 4.1 10 30 54 Example 10 34 4.2 10 29 49 Comparative A1 4.5 10 25 76 Example A1 Comparative B1 4.7 10 22 78 Example B1 Comparative C1 4.4 10 24 65 Example C1

TABLE 4 Dopant compound No. in Emission λ_(max) Lifespan (LT₉₇) layer (nm) (Relative value, %) Example 1 4 622 200 Example 2 1 622 185 Example 3 6 625 160 Example 4 7 623 180 Example 5 9 629 230 Example 6 16 622 150 Example 7 18 624 130 Example 8 23 627 140 Example 9 28 626 170 Example 10 34 622 300 Comparative A1 614 90 Example A1 Comparative B1 605 95 Example B1 Comparative C1 631 70 Example C1

Referring to Tables 3 and 4, the FWHM of light emitted from the organic light-emitting devices of Examples 1 to 10 was smaller than the FWHM of light emitted from the organic light-emitting devices of Comparative Examples A1 to C1. Accordingly, it was confirmed that the organic light-emitting devices of Examples 1 to 10 had higher color purity levels than the organic light-emitting devices of Comparative Examples A1 to C1. It was confirmed that the organic light-emitting devices of Example 1 to 10 have improved characteristics compared to the organic light-emitting device of Comparative Example A1 to C1 in terms of the driving voltage, external quantum efficiency, and lifespan.

The organometallic compounds, according to embodiments of the disclosure, have excellent characteristics in terms of quantum luminescence efficiency and the horizontal orientation ratio. Thus, the emission peak of the electroluminescent spectrum of an organic light-emitting device including the organometallic compounds has a relatively narrow FWHM, and an organic light-emitting device including the organometallic compound may have excellent external quantum efficiency and lifespan characteristics.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the following claims. 

What is claimed is:
 1. An organometallic compound represented by Formula 1:

wherein, in Formula 1, Y₂ is C, ring A₂ is a C₅-C₃₀ carbocyclic group or a C₁-C₃₀ heterocyclic group, R₁ to R₈, R₁₃ to R₁₇, and R₂₀ are each independently hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉>, or —P(Q₈)(Q₉), d2 is an integer from 0 to 10, and when d2 is 2 or more, two or more R₂₀(s) are identical to or different from each other, i) at least one of R₁ to R₈ is —CH₂F, —CHF₂ or —CF₃, and ii) R₂₀ comprises neither a fluoro group (—F) nor a cyano group, R₁₈ and R₁₉ are each independently a substituted or unsubstituted C₂-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₁₀ aryl group, a substituted or unsubstituted C₆-C₁₀ aryloxy group, a substituted or unsubstituted C₆-C₁₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, or a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, two or more of R₁ to R₈ are optionally linked to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a), two or more of R₂₀(s) in the number of d2 are optionally linked to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a), two or more of R₁₃ to R₁₉ are optionally linked to form a C₅-C₃₀ carbocyclic group which is unsubstituted or substituted with at least one R_(1a) or a C₁-C₃₀ heterocyclic group which is unsubstituted or substituted with at least one R_(1a), R_(1a) is the same as explained in connection with R₂, a substituent of the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₂-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₂-C₁₀ heterocycloalkenyl group, the substituted C₆-C₁₀ aryl group, the substituted C₆-C₁₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀ heteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, or a C₁-C₆₀ alkoxy group, each substituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀ aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), —P(═O)(Q₁₈)(Q₁₉), —P(Q₁₈)(Q₁₉), or any combination thereof; a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀ aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, or a monovalent non-aromatic condensed heteropolycyclic group, each unsubstituted or substituted with deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, a phosphoric acid or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₂-C₁₀ heterocycloalkenyl group, a C₆-C₁₀ aryl group, a C₆-C₁₀ aryloxy group, a C₆-C₁₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), —P(Q₂₈)(Q₂₉), or any combination thereof; —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), or —P(Q₃₈)(Q₃₉); or any combination thereof, wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are each independently hydrogen; deuterium; —F; —Cl; —Br; —I; a hydroxyl group; a cyano group; a nitro group; an amidino group; a hydrazine group; a hydrazone group; a carboxylic acid group or a salt thereof; a sulfonic acid group or a salt thereof; a phosphoric acid group or a salt thereof; a C₁-C₆₀ alkyl group, unsubstituted or substituted with deuterium, a C₁-C₆₀ alkyl group, a C₆-C₆₀ aryl group, or any combination thereof; a C₂-C₆₀ alkenyl group; a C₂-C₆₀ alkynyl group; a C₁-C₆₀ alkoxy group; a C₃-C₁₀ cycloalkyl group; a C₂-C₁₀ heterocycloalkyl group; a C₃-C₁₀ cycloalkenyl group; a C₂-C₁₀ heterocycloalkenyl group; a C₆-C₁₀ aryl group, unsubstituted or substituted with deuterium, a C₁-C₆₀ alkyl group, a C₆-C₁₀ aryl group, or any combination thereof; a C₆-C₁₀ aryloxy group; a C₆-C₁₀ arylthio group; a C₁-C₆₀ heteroaryl group; a monovalent non-aromatic condensed polycyclic group; or a monovalent non-aromatic condensed heteropolycyclic group.
 2. The organometallic compound of claim 1, wherein ring A₂ is a benzene group, a naphthalene group, a 1,2,3,4-tetrahydronaphthalene group, a thiophene group, a furan group, a pyrrole group, a cyclopentadiene group, a silole group, a benzothiophene group, a benzofuran group, an indole group, an indene group, a benzosilole group, a dibenzothiophene group, a dibenzofuran group, a carbazole group, a fluorene group, or a dibenzosilole group.
 3. The organometallic compound of claim 1, wherein R₁ to R₈, R₁₃ to R₁₇, and R₂₀ are each independently hydrogen, deuterium, —F, a substituted or unsubstituted C₁-C₂₀ alkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₂-C₁₀ heterocycloalkyl group, —Si(Q₃)(Q₄)(Q₅), or —Ge(Q₃)(Q₄)(Q₅).
 4. The organometallic compound of claim 1, wherein R₁ to R₈ and R₁₃ to R₁₇ are each independently: hydrogen, deuterium, or —F; a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, —F, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof; or —Si(Q₃)(Q₄)(Q₅) or —Ge(Q₃)(Q₄)(Q₅), and R₂₀ is hydrogen or deuterium; a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₆₀ heterocycloalkyl group, or any combination thereof; or —Si(Q₃)(Q₄)(Q₅) or —Ge(Q₃)(Q₄)(Q₅).
 5. The organometallic compound of claim 1, wherein R₁₈ and R₁₉ are each independently an unsubstituted or substituted C₂-C₆₀ alkyl group, an unsubstituted or substituted C₃-C₁₀ cycloalkyl group, or an unsubstituted or substituted C₂-C₁₀ heterocycloalkyl group.
 6. The organometallic compound of claim 1, wherein R₁₈ and R₁₉ are each independently a C₂-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₆₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, —F, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.
 7. The organometallic compound of claim 1, wherein at least one of R₄ to R₈ is —CH₂F, —CHF₂ or —CF₃.
 8. The organometallic compound of claim 1, wherein one or two of R₁ to R₈ each independently is —CH₂F, —CHF₂ or —CF₃, and at least one of R₁ to R₈ i) does not comprise a fluoro group (—F), and ii) is not hydrogen.
 9. The organometallic compound of claim 1, wherein a group represented by

 in Formula 1 is a group represented by one of Formulae CY1 to CY88:

wherein, in Formulae CY1 to CY88, T₄ to T₈ are each independently —CH₂F, —CHF₂ or —CF₃, each of R₂, R₄ to R₈, and R_(1a) are the same as described in claim 1, and R₂ and R₄ to R₈ are not hydrogen, * indicates a binding site to Ir in Formula 1, and *″ indicates a binding site to a neighboring atom in Formula
 1. 10. The organometallic compound of claim 10, wherein R₂ and R₄ to R₈ in Formulae CY1 to CY88 are each independently: deuterium; or a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₁-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₆₀ heterocycloalkyl group, or any combination thereof.
 11. The organometallic compound of claim 1, wherein a group represented by

 in Formula 1 is a group represented by one of Formulae A(1) to A(7):

wherein, in Formulae A(1) to A(7), Y₂ is C, X₂ is O, S, N(R₂₅), C(R₂₅)(R₂₆), or Si(R₂₅)(R₂₆), each of R₉ to R₁₂ and R₂₁ to R₂₆ are the same as described in connection with R₂₀ in claim 1, *′ indicates a binding site to Ir in Formula 1, and *″ indicates a binding site to a neighboring atom in Formula
 1. 12. The organometallic compound of claim 11, wherein R₉ and R₁₁ in Formula A(1) are each independently a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, or a C₂-C₁₀ heterocycloalkyl group, each unsubstituted or substituted with deuterium, a C₁-C₂₀ alkyl group, a C₃-C₁₀ cycloalkyl group, a C₂-C₁₀ heterocycloalkyl group, or any combination thereof.
 13. The organometallic compound of claim 1, wherein none of R₁₄ and R₁₆ is hydrogen.
 14. The organometallic compound of claim 1, wherein a number of carbons in a group represented by *—C(R₁₃)(R₁₄)(R₁₉) in Formula 1 is 5 or more, and a number of carbons in a group represented by *—C(R₁₆)(R₁₇)(R₁₈) in Formula 1 is 5 or more.
 15. The organometallic compound of claim 1, wherein the organometallic compound is at least one of Compounds 6 to 8, 12, 17, 27, 28 and 38 below:


16. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode and comprising an emission layer, wherein the organic layer comprises at least one organometallic compound of claim
 1. 17. The organic light-emitting device of claim 16, wherein the first electrode is an anode, the second electrode is a cathode, the organic layer further comprises a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode, the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof, and the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 18. The organic light-emitting device of claim 16, wherein the organometallic compound is included in the emission layer.
 19. The organic light-emitting device of claim 18, wherein the emission layer emits red light. 